Power reverse gear mechanism



July 3, 1928. 1,675,576

. I M. H. ROBERTS POWER REVERSE GEAR MECHANISM Filed Feb. 7, 1924 2 Sheets-Sheet l INVENTOR WAAM BY A T'I'ORNEVJ M. H. ROBERTS POWER REVERSE GEAR MECHANISM July 3, 1928.

Filed Feb. 7, 1924 2 Sheets-Sheet IN VEN TOR A TTOPNEV5 Patented July 3, 1928.

UNITE-D STATES PATENT "OFFICE;

non-menu H. meme, or nnernwoon, New was, Msmnon'no Imam WAY SUPPLY comranr, osnnwxoax, N.;Y.,. a oonronnron 01a imuwm rowan enaamnonamsml jjj Original application filed February 26, 1921, Serial "no? 448,044. Divided and on; application filed February 7, 1924.

This invention relates to powerreverse gear mechanism and is a division of mycopending application Serial No. 448,044, filed February 26th, 1921, and sinceissued as Patent No. 1,500,685, on July 8, 1924:.

' The reversegear ofthe aforesaid. application is one in whichthereis a direct 0011- nection betweenthevalve.and the piston, which is manually variable toinove the valve to actuate the piston to adjust'cut-ofi, but which is of such character that when the piston moves under load, shock, thrust or drop in pressure or similar cause, the

valve is caused to move withthe piston to automatically restore the piston to the reselectedposition. .The'connection, asi lusthreaded shaft and, since the piston of a reverse gear has considerable strokeusually in the neighborhood of 18the thread must be of a length at least equal to the stroke of the piston.

The screw threaded shaft is operated from the cab by a hand wheel and a suitable connection, the hand operating means being employed to actuate an indicator which indicates the position of the piston and, therefore, the cutoff of the valve, or the speed if desired. It is impractical, particularly in locomotive service, to have an indicating mechanism which has a stroke as long as that of the piston.

It is the primary object of this invention to provide an arrangement of means associated with a gear of this character whereby the indication is on a reduced or proportional scale making it possible to secure the desired compactness of the indicating mechanism.

The foregoing, together with such other objects as may hereinafter appear, or are incident to my invention, I obtain by means of a construction which I have illustrated in preferred form in the accompanying drawings wherein:

Fig. 1, is a diagrammatic side elevation of a portion of a locomotive, illustrating the reverse gear and its hand operating means, together with the indicator;

Fig. 2, is a plan view of the hand operating wheel and the indicator, drawn on an enlarged scale;

Fig. 3, is a side elevation of Fig. 2; and

Serial No. 691,218.

grow to 1, thereference denotes the gear,indicated as varied to actuate the valve to move the piston to adj'ustcutvofi and also to be automatically mo'ved when the piston moves from any selected position of adjustment to cause the valve to "move with itto rectify the position of the piston The shaft 10 has threaded engagement. with thehut 11 carried on thepistou rod 12of the piston. trated in said application, comprises a screw The screwshaft 10 is operated from the cab by means of the handwheel 13 andthe shaftmgli The thr eaded" ortionof the part housing 18, the parts of which are constructed so as to leave a slot 17 inthe top thereof, and that the shaft 14?" has a screw thread 15 the threads of which have a less pitch than the threads of the shaft 10, in this case one-half. The threaded portion 15 is, therefore, one-half the length of the threaded portion of the shaft 10. Mounted on the threaded portion 15 is a square nut 16 having a pointer 17. The nut is prevented from turning by means of the box 18 in which the shaft 14 is mounted. The upper face of the box is graduated as indicated in Fig. 2 to indicate the percent of cutoff and also miles per hour.

When the shaft 10 is rotated to effect an adjustment, the nut 16 is moved in an amount one-half that of the adjustment of the shaft 10 with reference to the piston, and thus the indicator mechanism is made simple and compact and available for use in the limited space afforded in the cab which, as those skilled in the art will readily understand, is crowded with mechanism and instruments.

In order to lock the parts in desired positions of cut off, I provide the hand latch 13 mounted on the housing 18 and adapted to engage any one of the notches 13 in the hand wheel hub. No load is transmitted to this lock, and neither does it interfere in the slightest degree with the automatic operation of the gear parts.

I claim:

1. A cut-off indicator for power reverse gears comprising in combination, a screw shaft, a nut on said shaft having a protruding indicator thereon and a split casing adapted to house the shaft and nut and providing an elongated o ening at the s lit through which said in icator isadapte to protrude.

2. A cut-off indicator for power reverse gears comprising in combination, a screw shaft, a nut on said shaft having a protruding indicator thereon and a split casing adapted to house the shaft and nut and providing an elongated opening at the split through which said indicator is adapted to protrude, together witha cut-ofi' indicating scale on one part of said casing adjacent said Opening.

3. A cut-ofi indicator for'power reverse gears comprising in combination, a screw shaft, a nut on said shaft having a protruding indicator thereon and a split casing adapted to house the shaft and nut and providing an elongated opening at the split through which said-indicator 18 adapted to protrude, together with a cut-ofi indicating scaleon one part of said casing adjacent said opening, and a miles per hour indicating scale on another part of said casing adjacent said opening.'

4. A cut-ofi indicator for power reverse gears comprising in combination, a, screw shaft, a nut on said shaft having indicating means associated therewith, and a casing adapted to house said shaft and nut, together with upstanding guideways on the interior of said casing extending longitudinally of said screw and adaptedto engage the nut and prevent its rotation:

5. A cut-off indicator for power reverse gears comprising in combination, a screw shaft, a nut on said shaft and a split casing enclosing the shaft and nut and providing bearings for said shaft, together with an elongated opening at a split in the casing and an indicator. associated with said nut adapted to protrude through said openings. .In testimony whereof, I have hereunto signed my name.

MONTAGUE' H. ROBERTS. 

